Polymer concrete with improved substrate adhesion

Abstract: Composition for preparing a polymer concrete with improved substrate adhesion, a method of protecting or reconditioning substrates by treatment with the composition, the protected or reconditioned surfaces thus treated, and multipackage systems for bringing the components of the application to the substrate site, wherein the composition comprises (1) an aggregate component ; (2) a monomer binder component in an amount effective to bind the aggregate component, upon curing, into a polymer concrete ; (3) a crosslinking-effective amount of a metal salt of an α, β-ethylenically unsaturated carboxylic acid ; and (4) a polymerization catalyst.

Description: This invention relates to polymer concrete having improved adhesion to substrates. In particular, this invention relates to a composition for preparing a polymer concrete in which metal salts of α, β-ethylenically unsaturated carboxylic acids are utilized to improve adhesion of the polymer concrete to substrates. "Polymer concrete", as used herein, is a composite material formed by polymerizing a liquid monomer in admixture with an aggregate. The polymerized liquid monomer serves as a binder for the aggregate. The liquid monomer typically contains one or more monomers and polymerization additives, i.e., catalysts. Additionally, the liquid monomer may include crosslinking agents, coupling agents, initiators, solvents, dissipators, surfactants, accelerators and viscosity control compounds. Polymer concrete materials are prepared from substantially anhydrous compositions. Polymer concrete materials are to be distinguished from polymer-impregnated concrete and polymer-portland cement concrete. Polymer-impregnated concrete is a precast portland cement concrete subsequently impregnated with a monomer that is polymerized in situ . Polymer-portland cement concrete is a premixed material in which either a monomer or a polymer is added to a fresh concrete mixture in a liquid, powder or dispersed phase and subsequently polymerized, if needed, and cured. Polymer concrete compositions, polymer-impregnated concrete, and polymer portland cement concrete are reviewed in Chemical, Polymer and Fiber Additives for Low Maintenance Highways, edited by G.C. Hoff et al. Chemical Technology Review No. 130, Noyes Data Corporation, Park Ridge, N.J., 1979 and Chemical Materials for Constructions, Phillip Maslow, Structures Publishing Company, Farmington, Michigan, 1979. Representative patents regarding polymer concrete materials are US-A-4,500,679 and US-A-4,460,625. Generally, a composition for preparing a polymer concrete is a substantially non-aqueous slurry of an aggregate component, a monomer binder component and a polymerization catalyst. These components may be packaged separately and mixed on-site to avoid premature polymerization. Monomers used as binders include, but are not limited to, methyl methacrylate and styrene used singly or in admixture and, at times, with other monofunctional monomers or with polyfunctional monomers such as trimethylolpropane trimethacrylate. Polyester-styrene, furan, vinyl ester and epoxy resins and oligomers have also been used in preparing polymer concretes, in each case in combination with suitable catalysts for initiating and/or accelerating the curing of the compositions. In conventional polymer concrete materials, the monomer binder component typically cures and sets rapidly. Additionally, the monomer binder component also generally exhibits shrinkage along with a consequent dewetting of the substrate to which the polymer concrete is applied. The polymer concrete provided by the compositions and methods of the present invention exhibits improved substrate adhesion while maintaining the rapid set times of the conventional polymer concrete. It has been discovered that it is possible to provide a polymer concrete which exhibits improved adhesion to substrates, but which maintains a rapid set-time. Accordingly, one aspect of the invention is a composition for preparing a polymer concrete comprising : (a) an aggregate component ; (b) a monomer binder component in an amount effective to bind the aggregate component, upon curing, into a polymer concrete ; (c) a crosslinking-effective amount of a metal salt of an α, β-ethylenically unsaturated carboxylic acid ; and (d) a polymerization catalyst. In another aspect of the invention, a method for protecting or reconditioning a substrate is provided wherein the substrate is coated, patched or impregnated with the aforesaid slurry, and the slurry is then permitted to cure under ambient conditions. Another aspect of the invention includes the surface obtained by practice of the method of the invention. Yet another aspect of the invention includes, as an article of manufacture, a multi-package system for admixture at the site of the substrate, wherein the packages comprise : (A) an aggregate component, a monomer binder component, a metal salt of an α, β-ethylenically unsaturated carboxylic acid, and a polymerization catalyst, respectively, or (B) an aggregate component and a monomer binder component, and a metal salt of an α, β-ethylenically unsaturated carboxylic acid respectively, together with a polymerization catalyst in the aggregate package or distributed between the aggregate and monomer binder packages. As used herein, "substrate" shall mean metal, wood, cement, conventional concrete, mortar, asphalt, glass, rubber and plastic. The present invention is based on the unexpected discovery that metal salts of certain α, β-ethylenically unsaturated carboxylic acids, specifically the metal salts of acrylic and methacrylic acids, when used as coagents to promote crosslinking in the processes and compositions herein disclosed, yield a polymer concrete with markedly improved adhesive properties with respect to substrates. This result is surprising because one would expect the addition of the unsaturated carboxylic acid metal salt to decrease adhesion of the polymer concrete to substrates. The α, β-ethylenically unsaturated carboxylic acid metal salts that may be employed in the present invention have at least one carboxylic group ionically bonded to metals. The unsaturated carboxylic acid that may be used include acids such as acrylic and methacrylic acids. The metal component of the unsaturated carboxylic acid metal salt may include, without limitation, magnesium, calcium, barium, titanium, molybdenum, iron, nickel, potassium, silver, cadmium, mercury, aluminium, lead, antimony and zinc. The preferred metals are calcium, magnesium, and zinc. Zinc is particularly preferred. The unsaturated carboxylic acid metal salts that may be utilized in the present invention correspond to the general structural formula shown in the formula below : in which R and R' are independently selected from the group consisting of hydrogen, hydroxyl, alkyl, alkenyl, alkynl, aryl, aralkyl, and alkaryl, Me is a metal atom selected from the above-listed metals and n is an integer from 1 to 6. The unsaturated carboxylic acid metal salt may be added to the aggregate component, to the monomer binder component or to the polymer concrete composition after blending. The unsaturated carboxylic acid metal salt is preferably added to the monomer binder component. The amount of the unsaturated carboxylic acid metal salt to be used in the present invention should be an amount effective to promote crosslinking. More specifically, the unsaturated carboxylic metal salt should be present in an amount from between about 1 to about 25 parts by weight of the aggregate component, or from between 2.5 to about 750 parts by weight of the monomer binder component, or from between about 1 to about 15 parts by weight of the polymer concrete composition. Preferably, amounts of from between about 5 to about 10 parts by weight of the polymer concrete composition are used. The preferred metal salt is zinc diacrylate. The aggregate component of the polymer concrete compositions of the present invention may be any inert inorganic particulate substance. Typically the aggregate component is sand, gravel, crushed stone or rock of various types, pebbles and finely divided materials such as portland cement, powdered chalk, clay, fly ash and silica flour and the like or mixtures thereof. Generally the aggregate will be selected to give a void volume which will require minimal amounts of monomer binder component to fill the voids and to give good workability. It is known that for a well-graded aggregate, larger maximum particle sizes require less resin, but that smaller maximum particle sizes produce higher strength in the polymer concrete. Accordingly, depending upon the type and viscosity of the monomer binder component, one skilled in the art can select appropriate aggregate gradation, maximum particle size and composition for balance of amount of monomer binder and desired polymer concrete strength. A typical composition will contain aggregate component and monomer binder component in proportions ranging from about 9 : 1 to about 1 : 5, preferably from about 5 : 1 to about 1 : 1 The monomer binder component may contain one or more monomers. A first binder is preferably a compound selected from isodecyl methacrylate, cetyl stearyl methacrylate, dodecyl pentadecyl methacrylate, cetyl eicosyl methacrylate, stearyl methacrylate, isobornyl methacrylate, and dicyclopentenyl or dicyclopentenyloxyalkyl (meth) acrylate. These compounds and methods for their preparation are disclosed in US-A-4,097,677. Preferably, at least one member is selected from dicyclopentenyloxyethyl methacrylate, dicyclopentenyloxyisopropyl methacrylate, dicyclopentenyloxyethyl acrylate, dicyclopentenyloxyisopropyl acrylate, and dicyclopentenyloxyneopentyl methacrylate. A second binder may be used along with the first binder in a two-binder system. A hydroxyalkyl methacrylate such as hydroxyethyl methacrylate is preferably used as the second binder. The relative amounts of monomer binder component used will depend on the surface area and porosity of the aggregate component. The amount of monomer binder component used should generally be between about 2 % to about 40 % by weight, preferably from about 15 % to about 20 %, of the total weight of the polymer concrete composition. When a two-binder system is used, the proportions of the first binder and the second binder may vary from about 25 % to about 75 % by weight respectively, based on the total of monomer binder component. A known catalyst system appropriate for the polymerization of the particular monomer binder component selected will be used. Typically, the polymerization catalyst is of a non-radiation responsive type. Suitable catalysts are, for example, organic peroxides or hydroperoxides in combination with a metal salt or complex accelerator. If only a peroxide or hydroperoxide is utilized, it may be necessary to heat the polymer concrete composition to induce curing. The organic peroxides and hydroperoxides, that may be used in the present invention include, but are not limited to, the peroxides and hydroperoxides derived from hydrocarbons which contain from about 3 to 18 carbon atoms so that they are soluble in the monomer binder component. Suitable organic hydroperoxides include tertiary-butylhydroperoxide, cumene hydroperoxide, methyl ethyl ketone hydroperoxide and diisopropylbenzene hydroperoxide. Suitable organic peroxides include benzoyl peroxide, tert-butylperbenzoate, 2,2-bis-(tertbutylperoxy)-butane, bis-(1-hydroxy-cyclohexyl)-peroxide, tert-butylperoxy-isopropyl carbonate, and ethyl methylketone peroxide. Metal salt accelerators that may be used in the polymerization catalyst of the present invention include, without limitation, metal-containing salts that catalyze the oxidative curing of drying oils. These metal salts are also known as "siccatives" or "driers". Such substances include the metal salts of higher aliphatic acids, such as the butyrate, pentanoate, hexanoate and especially the salts of acids having from 8 to about 30 carbon atoms, or of naphtenic acids that provide solubility in the binder component. Generally, the proportions of organic peroxide or hydroperoxide to accelerator used are about 20 : 1 to about 1 : 1 by weight. Typically, the most useful drier salts for the monomer binder component of the present invention are salts of naphtenic acids. Examples of the metal component of the salts include calcium, copper, zinc, manganese, potassium, lead, cobalt, iron, vanadium, and zirconium. Preferred drier salts are those of cobalt, potassium, and calcium such as cobalt naphtenate, potassium naphtenate, and calcium naphtenate. Particularly preferred is cobalt naphtenate. The metal salt and organic peroxide or hydroperoxide can be added to the monomer binder component prior to application. The proportion of metal salt added before application may be from between about 0.0005 % to about 2 % by weight, and the amount of organic peroxide or hydroperoxide may be in the range of from between about 0.1 to about 3 weight percent based on the total weight of the monomer binder component. Similarly, the addition of an organic peroxide with an aromatic amine, and optionally with a metal salt, can be made prior to application. The proportion of the organic peroxide to the monomer binder component may be from between about 0.1 to about 3 weight percent and the aromatic amine accelerator is utilized in an effective amount, generally from between about 0.1 to about 5 weight percent of the monomer binder component. Exemplary aromatic amines include aniline, N,N-dimethylaniline, N,N-diethylaniline, toluidine, N,N-dimethyl p-toluidine, N,N-di(hydroxyethyl) toluidine, and p-dimethylaminobenzaldehyde. The polymerization catalyst components may be packed and shipped separately to the site of use of the compositions of the present invention where the components may be combined. Alternatively, the aromatic amine accelerator, monomer binder component and the organic peroxide may be combined in packages for storing and shipping prior to combining them to provide the composition of the invention shortly before applying the composition. When the components of the polymer concrete composition of the present invention are packaged separately the organic peroxide or hydroperoxide may be pre-mixed with the aggregate component and the metal salt accelerator may be premixed with the monomer binder component. The polymer concrete compositions of the invention may also contain various additives depending on the desired properties and effects. Fillers and flow control agents of various types may be added to assist in application and to modify the properties of the cured polymer concrete composition. Coloring agents such as pigments or dyes may be added to the aggregate component or to the polymer concrete composition after blending. The addition of coloring material or other agents may require dispersion of the additive in an aqueous medium, alone or in admixture with an emulsifier or surfactant, prior to blending with the polymer concrete composition or a component thereof. The presence of these minor amounts of water is not intended to be excluded by the term "substantially anhydrous" as a condition for the polymer concrete compositions of the present invention. The components of the compositions of the present invention may be admixed in any manner suitable for control of the polymerization of the monomer binder component and convenient use of the polymer concrete composition. For example, the metal salt, aggregate component, monomer binder component, and polymerization catalyst may be brought to the application site in separate packages and then mixed either manually or by use of known metering/blending devices in the requisite proportions and sequencing to obtain a polymer concrete composition having a viscosity and pot-life appropriate for the intended application. For example, if the application is discrete patching of a substrate, a short pot-life of several minutes or hours may be acceptable. In contrast, if the application is continuous or in large quantities, such as reconditioning of a substrate by continuous coating, resurfacing or impregnating, a pot-life of 4 to 8 hours or more may be required. In all applications, the ambient temperature is an important consideration from the standpoint of the cure rate desired for the application. The skilled formulator and applicator of polymer concrete compositions is well aware of these and other conditions and can readily select elements of the polymer concrete compositions and proportions as well as mode of application suited to the specific use. The polymer concrete compositions of the present invention may be used in a wide variety of circumstances for the protection and/or reconditioning of substrates by any conventional application technique, such as coating, patching, impregnating, or other technique. Exemplary uses include to form, or patch, previously formed or laid concrete floors, roads or bridge abutments, and as industrial coatings to prevent acoustic or acid-corrosion of platforms, reactors, dam structures, industrial passages and the like. Additionally, the compositions of the present invention may be used to form, or patch, parking lots, patios and driveways. The invention will be further clarified by a consideration of the following examples which are intended to be purely exemplary of the use of the invention. In the following examples, all of the ingredients are expressed in parts by weight, unless otherwise noted. The testing procedure used for examples 1-17, the results which are summarized in Tables 1 and 2 herein, was as follows : The polymer concrete composition was weighed into a 50 ml. beaker and a 25,4 mm by 101,6 mm metal test strip was submerged into the center of the composition on end so that the strip was perpendicular to the composition's surface with an approximately 12,7 mm overlap. The composition was then cured. Shear bond adhesion was subsequently tested utilizing a Thwing - Albert Intellect-II STD Tensile Tester. The shear bond adhesion reported was calculated as the force required to pull the metal strip out of the cured composition measured in pounds per square inch. EXAMPLE 1 An aggregate was prepared by uniformly mixing general purpose sand and silica (120 µ) in a ratio of 15 parts of silica to 70 parts of sand. The aggregate was slurried with 15 parts of dicyclopentenyloxyethyl acrylate (DCPOEA) and thoroughly mixed. 0.3 parts of cumene hydroperoxide was mixed into the slurry followed by the addition of 0.1 parts of 6 % cobalt naphtenate and mixed thoroughly. The polymer concrete composition was then prepared for shear bond adhesion testing as described hereinabove and then cured at 25°C overnight and post-cured for 7 days. The composition was then tested as previously described. EXAMPLES 2-4 Polymer concrete compositions were prepared and cured by repeating the procedure of Example 1 except that the recipes which may be found on Table 1 were followed. EXAMPLES 5-9 Polymer concrete compositions were produced by repeating the procedure of Example 1 except that the recipes which may be found on Table 1 were followed. The compositions were prepared for shear bond adhesion testing as described hereinabove and then cured at 25°C for 72 hours. The compositions were subsequently tested as previously described. EXAMPLES 10-11 Polymer concrete compositions were produced by repeating the procedure of Example 1 except that the recipes which may be found on Table 1 were followed. The compositions were prepared for shear bond adhesion testing as described hereinabove and then cured in a forced air oven at 90°C for 4 hours. The compositions were subsequently tested as previously described. EXAMPLE 12 A polymer concrete composition prepared by dry blending 63.3 parts of sand, 5.5 parts of silica and 6.7 parts of zinc diacrylate. The aggregate was then slurried with 15.0 parts of DCPOEA and 9.1 parts of hydroxyethyl methacrylate (HEMA) followed by the addition of 0.1 parts of 6 % cobalt naphtenate. After thorough mixing, 0.3 parts of cumene hydroperoxide was added and the mixture vigorously mixed. The composition was then prepared for shear bond adhesion testing as described hereinabove and cured in a forced air oven at 80°C for 1.5 hours. The composition was subsequently tested as described above. EXAMPLES 13-17 Polymer concrete compositions were produced by repeating the procedure in Example 12 except that the recipes which may be found on Table II were followed.

Claims: A composition for preparing a polymer concrete, comprising : (a) an aggregate component ; (b) a monomer binder component in an amount effective to bind the aggregate component, upon curing, into a polymer concrete ; (c) a crosslinking-effective amount of a metal salt of an α, β-ethylenically unsaturated carboxylic acid ; and (d) a polymerization catalyst. The composition of claim 1, wherein the metal salt of the α, β-ethylenically unsaturated carboxylic acid is a metal salt of acrylic acid or methacrylic acid. The composition of claim 2, wherein the metal salt is calcium diacrylate, magnesium diacrylate, zinc diacrylate, or zinc dimethacrylate. A composition according to any of claims 1 to 3, wherein the metal salt of the α, β-ethylenically unsaturated carboxylic acid is present in an amount from between 1 to 25 parts by weight per 100 parts by weight of the aggregate component. A composition according to any of claims 1 to 3, wherein the metal salt of the α, β-ethylenically unsaturated carboxylic acid is present in an amount from between 2.5 to 750 parts by weight per 100 parts by weight of the monomer binder component. A composition according to any of claims 1 to 3, wherein the metal salt of the α, β-ethylenically unsaturated carboxylic acid is present in an amount of from between 1 to 15 parts by weight per 100 parts by weight of the polymer concrete composition. A composition according to any of claims 1 to 6, wherein the monomer binder component is selected from dicyclopentenyloxyalkyl methacrylates and dicyclopentenyloxyalkyl acrylates. A composition according to any of claims 1 to 7, wherein the monomer binder component is present in an amount of from between 2 % to 40 % of the weight of the polymer concrete composition. A composition according to any of claims 1 to 8, further comprising a second binder. The composition of claim 9, wherein the second binder is a hydroxyalkyl methacrylate. A method for protecting or reconditioning a substrate, which comprises the steps of coating, patching or impregnating the substrate with a polymer concrete composition comprising : (a) an aggregate component ; (b) a monomer binder component in an amount effective to bind the aggregate component, upon curing, into a polymer concrete ; (c) a crosslinking-effective amount of a metal salt of an α, β-ethylenically unsaturated carboxylic acid ; and (d) a polymerization catalyst. and permitting the polymer concrete composition to cure under ambient conditions. The protected or reconditioned substrate obtained by the method of claim 11. A multi-package system adapted to be stored, transported to the site of use, and to be mixed to form a polymer concrete slurry hardenable under ambient conditions to a polymer concrete, wherein the packages separately comprise : (A) the aggregate component, the monomer binder component, the metal salt of the α, β-ethylenically unsaturated carboxylic acid, and the polymerization catalyst of claim 1, respectively, or (B) the aggregate component, the monomer binder component, and the α, β-ethylenically unsaturated carboxylic acid metal salt of claim 1, respectively, together with a polymerization catalyst in the aggregate package or distributed between the aggregate and monomer binder packages.

Inventors: BAILEY MICHAEL A, COSTIN RICHARD C, NAGEL WALTER R, BAILEY, MICHAEL A., COSTIN, RICHARD C., NAGEL, WALTER R.
Applicants: SARTOMER CO INC, SARTOMER COMPANY, INC.
Application year: 1994
Main classification: C04B26
IPC codes: C04B26, C04B41